It is now common in electronic apparatus such as mobile cellular telephones, for a user to provide user commands to the apparatus via touch input. A touch input in this sense may involve the user actually touching the device or putting their finger or input device in close proximity to the apparatus.
It is possible to detect a touch input, for example, by measuring a capacitance at a capacitive sensor electrode. The presence of a user input device such as a finger changes the capacitance of the capacitive sensor electrode and this changed capacitance may be measured. In order to provide a high resolution of touch input detection over a touch area, it may be necessary to provide a large number of capacitive sensor electrodes in the touch area. Control circuitry also needs to be provided for measuring the capacitance at the capacitive sensor electrode.